There are two ways in which a celebrity can be sold in Celebrity Bucks. The first is by clicking the Sell Celebrities option from your Contest screen.
This will take you to your portfolio showing the list of celebrities that you currently own. You can only sell celebrities during your contest's Market Hours and as long as you haven't reached the Maximum Drops for the day.
To sell a celebrity, simply click the "Sell" button next to the celebrity.
Clicking the "Sell" button will tell Celebrity Bucks that you wish to sell this celebrity at the current Celebrity Bucks market price. Selling a celebrity removes the celebrity from your portfolio and the celebrity is then subject to the Waiver Period.
The second way that a celebrity can be sold is through a Celebrity Bucks tool like the Watchlist. This tool is designed to allow players to monitor the pricing and availability of any celebrity across all of that player's active contests.
Let's consider the following scenario: We are involved in 5 different Celebrity Bucks contests and we believe that a particular celebrity's value has peaked. If that celebrity is on our watchlist, we can immediately see which contests that celebrity is in along with our cash position and the celebrity's price in each contest. We can then sell that celebrity from the Watchlist without having to actually go into the contest, click the Sell Celebrities button, find, and sell the celebrity. We can accomplish what we want in a matter of seconds instead of minutes.